This invention relates generally to knife handles adaptable for mounting a replaceable blade. More particularly, this invention relates to a knife handle for a utility knife employing a blade carrier for mounting a blade which carrier is either fixed within the handle or may be slidably moved from a sheathed position wherein a mounted blade is enclosed within the handle to an extended, unsheathed position wherein the knife blade projects through an opening in the handle to present a cutting edge.
Exemplary types of knife handles to which the present invention is particularly related are disclosed in U.S. Pat. No. 3,107,426, issued to W. H. Robinson, Jr., U.S. Pat. No. 3,872,591 issued to Michel Quenot, U.S. Pat. No. 3,577,637 issued to Paul A. Braginetz, U.S. Pat. No. 4,242,795 issued to Ernest J. Rollband and Robert F. West. Such utility knives incorporate a blade carrier which mounts and supports a blade at the interior of the handle for longitudinal movement therein. The blade carrier incorporates a thumb actuated button that can be depressed to unlatch the blade from one of several latch positions for shifting the blade via the carrier to another longitudinal position. The thumb actuated button may extend through a slot in the top of the knife handle and is secured to the blade carrier by means of a resilient finger. The knife handle is further adapted so that the blade may be relatively easily dismounted and replaced. The blades are replaced through the front opening of the knife handle or by gaining access through the side of the knife handle. Such knives have found great popularity and are of great utility in a wide variety of cutting operations.
While the foregoing utility knives are relatively inexpensive to manufacture and generally operate in an efficient and safe manner, a continuing concern with respect to either standard side-loading utility knives or front-loading utility knives is that during very heavy duty use the blade not disengage from the carrier and either jamb in the knife handle or entirely disengage from the knife handle. The present invention is directed to further insuring that the knife blade does not disengage from the carrier during heavy duty cutting operations.